GSM-gateways and other “Polygator” equipment are result of own research and development done by our company. You may have a look at this article (Russian language) about how the development of the CPU-board is performed. This board is present in the GSM-gateways of G20 and G8 series. http://habrahabr.ru/post/238929/ (rus)

VoIP-GSM gateways G20/G8-series support GSM and UMTS (optional) networks, as well as they can be equipped with PRI, FXO and FXS ports thanks to modular architecture. This way you may have any telecommunication technologies together in this device. Besides, the device is based on Linux OS and ARM-processor capable of running Asterisk (universal IP-PBX www.asterisk.org), OpenVPN (VPN-network client), Kannel (SMS-server www.kannel.org) and other handy software «on board» for implementing extremely portable and cost-efficient solutions.